Female quick-connect coupling element, and a quick-connect coupling incorporating such an element

ABSTRACT

A female quick-connect coupling element for releasably joining pipes for pressurized fluid having a fluid flow duct and a valve for controlling the flow of fluid through the duct, wherein the valve has a first piston and a second piston that are mounted to move along a common axis (Y-Y′) relative to a body of the female element and wherein the first piston cooperates with a valve seat within the body of the female element, so as to close the valve, while the first and second pistons are interconnected via a mechanical link assembly and each of the pistons defines one of two opposite surfaces in contact with the fluid when the valve is open and wherein the mechanical link assembly is disposed outside the fluid flow duct.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a female quick-connect coupling element and to a quick-connect coupling that can be used for releasably joining together two pipes for pressurized fluid, and that includes, inter alia, such a female element.

2. Brief Description of the Related Art

In the field of releasably joining together pipes through which pressurized fluid flows, it is known that a female coupling element can be used that is provided with controlled locking means for locking a male element in a configuration in which it is fitted into the female element, i.e. in a configuration in which the pipes are interconnected, the male and female elements constituting ends of respective ones of said pipes. A female coupling element is generally provided with a control valve for controlling the flow of the pressurized fluid. It must be possible for said valve to be operated when fluid at very high pressure, in particular liquefied petroleum gas (LPG), is to be fed into a motor vehicle tank at pressures of about 300 bars. For that purpose, it is known that a valve can be used that has two pistons, each of which defines a respective one of the two opposite surfaces in contact with the pressurized fluid. The two pistons that must be operated simultaneously both in the opening direction and in the closure direction are interconnected via a rod that passes through the fluid flow duct and thereby reduces the flow section thereof. The forces exerted by the pressurized fluid on the two pistons put the rod under traction, and the section of said rod must be dimensioned in such a manner as to withstand said forces, making the rod more voluminous.

In addition, in particular if the gas that flows through the coupling is hydrogen, it is known that the action of that gas on a material subjected to traction stress has the effect of reducing the life of the material. This therefore requires the section of the rod to be increased, thereby making it more voluminous.

SUMMARY OF THE INVENTION

More particularly, an object of the invention is to remedy those drawbacks by proposing a novel female quick-coupling element that is provided with a valve that operates more reliably.

To this end, the invention provides a female quick-connect coupling element for releasably joining together pipes for pressurized fluid, said female element being equipped with a fluid flow duct and with a valve for controlling the flow of the fluid through the duct, the valve having a first piston and a second piston that are mounted to move along the same axis relative to a body of the female element, the first piston being suitable for co-operating directly or indirectly with a seat formed by the body of the female element, so as to close the valve, while the first and second pistons are interconnected via mechanical link means, and each of said pistons defines one of two opposite surfaces in contact with the fluid when the valve is open. Said female quick-connect coupling element is characterized in that the mechanical link means between the first and second pistons are disposed outside the fluid flow duct.

When the valve is open, the forces exerted by the fluid on each of the two pistons are opposing forces, and, depending on the dimensioning of said two opposite surfaces, said forces compensate or are unbalanced in the valve opening direction or in the valve closure direction. The second piston acts as a “compensation” piston.

By means of the invention, the link means between the first and second pistons can be dimensioned without hindering the flow of fluid through the fluid flow duct. In addition, said mechanical link means are not subjected to the chemical action of the fluid, such as hydrogen, thereby making it possible to increase the lifetime of said link means.

In advantageous but non-compulsory aspects of the invention, such a female coupling element may incorporate one or more of the following characteristics, taken in any technically feasible combination:

-   -   the mechanical link means between the first piston and the         second piston comprise a first plate drivingly linked to the         first piston, a second plate drivingly linked to the second         piston, and at least one link member interconnecting the first         and second plates, while the first and second plates are         disposed on either side of a portion of the flow duct that is         defined between opposite surfaces of the pistons, and while the         link member is mounted to move relative to the body of the         female element, along an axis parallel to the axis along which         the pistons move relative to said body.     -   the female quick-connect coupling has two link members between         the first plate and the second plate, which link members are         mounted to slide along the axis along which the two pistons move         in two recesses provided in the body of the female element;     -   at least one of the pistons is partially inserted into a         corresponding recess in the plate to which it is drivingly         linked, and radial clearance is provided between this piston and         this recess;     -   the first piston is partially inserted into a corresponding         recess in the first plate, and radial clearance is provided         between this piston and this recess;     -   the first piston is mounted to slide in leaktight manner in a         first bore in the body, and the second piston is mounted to         slide in leaktight manner in a second bore in the body;     -   the area of the cross-section of the second piston where it is         in leaktight contact with the second bore is greater than the         area of the cross-section of the first piston where it is in         leaktight contact with the first bore;     -   the first piston is mounted to slide in leaktight manner in a         bore in the body, and the cross-section of the first piston at         its zone where it bears against the seat or the cross-section of         a member pressed by the first piston against the seat has an         area greater than the area of the cross-section of the first         piston where it is in leaktight contact with the bore;     -   The female quick-connect coupling element is provided with at         least one lever that is hinged relative to the body about an         axis perpendicular to the axis along which the pistons slide,         the lever being drivingly linked to the mechanical link means,         while a first movement in rotation of the lever about the axis         causes the mechanical link means and the pistons to move in         translation in a first direction along the axis along which they         move, and while a second movement in rotation of the lever about         the axis, opposite to the first movement in rotation, causes the         link means and the pistons to move in translation in the other         direction along the axis along which they move;     -   the end of the first piston has a surface that is partially         spherical and that is suitable for coming to bear against the         seat when the valve is in the closed configuration; and     -   the first piston co-operates with the seat via a connection rod         suitable for coming to bear against the seat, and both of the         pistons are suitable for coming into contact with the ball at         their two opposite surfaces.

The invention also provides a quick-connect coupling for releasably joining together pipes for pressurized fluid, said coupling comprising two elements, namely a male element and a female element, which elements are suitable for fitting one into the other, said coupling being characterized in that the female element is a female element as mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood and other advantages of the invention appear more clearly from the following description of three embodiments of a female coupling element and of a coupling that comply with the principle of the invention, the description being given merely by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a coupling of the invention that incorporates a female element of the invention and a male element engaged in the female element without being locked therewith;

FIG. 2 is a plan view of the coupling of FIG. 1;

FIG. 3 is a section view on a larger scale on line III-III of FIG. 2, a portion of a pipe and of an actuation lever for actuating the female element being omitted in order to make the drawing clearer;

FIG. 4 is a view on a larger scale of the detail IV of FIG. 3;

FIG. 5 is a section view on a larger scale on line V-V of FIG. 3;

FIG. 6 is a section view analogous to FIG. 3, while the male element is being locked into the female element;

FIG. 7 is a section view on line VII-VII of FIG. 2, while the coupling elements are in the configuration of FIG. 6;

FIG. 8 is a section view analogous to FIG. 7, while the female element is coming into leaktight contact with a seal carried by the male element of the coupling;

FIG. 9 is a view on a larger scale of the detail IX of FIG. 8;

FIG. 10 is a section view analogous to FIG. 7, while a valve for controlling the flow of fluid inside the female element is being opened;

FIG. 11 is a view on a larger scale of the detail XI of FIG. 10;

FIG. 12 is a section view on the plane XII-XII of FIG. 2 while the coupling elements are in the configuration of FIGS. 10 and 11;

FIG. 13 is a section view on a larger scale on line XIII-XIII of FIG. 10;

FIG. 14 is a section view analogous to FIG. 7, while the valve of the female element is being closed and while a fluid present in the coupling is being emptied;

FIG. 15 is a view on a larger scale of the detail XV of FIG. 14;

FIG. 16 is a view analogous to FIG. 11 for a second embodiment of a coupling of the invention;

FIG. 17 is a view analogous to FIG. 15 for the coupling of FIG. 16; and

FIG. 18 is a section view comparable to FIG. 5, for a third embodiment of a coupling of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The quick-connect coupling R that is shown in FIGS. 1 to 14 comprises a female element A and a male element or end-piece B that are designed to fit one into the other along an axis X-X′ that, in practice, is a longitudinal axis that is common to the elements A and B.

By convention, it is considered that the front portion of an element A or B is that portion of said element that faces towards the other element on interconnecting them.

The rear portion of the female element A is in fluid connection with a first pipe C₁ that is itself connected to a pressurized fluid source (not shown), e.g. a source of a gas such as LPG or hydrogen at a pressure of about 300 bars. The rear portion of the male element B is connected to a second pipe C₂ that is itself connected to a member for using or for storing the fluid coming from the above-mentioned source. By way of example, the pipe C₂ may be connected to a tank on board a motor vehicle.

The male element B comprises a tubular body 11 to which the pipe C₂ is connected and that defines a fluid flow channel 12 through which pressurized fluid can flow. A non-return or “check” valve member 13 is mounted in the body 11 and comes to bear against a seat formed by a seal 14 received in an internal peripheral groove 15 in the body 11, under drive from a spring (not shown).

On its outside peripheral surface 16, the body 11 is provided with a circularly symmetrical peripheral groove 17 of profile defined by a bottom 17 a that is flat and by two edges 17 b and 17 c that diverge going away from the bottom 17 a. Thus, the bottom 17 a is circularly cylindrical whereas the edges 17 b and 17 c are frustoconical.

On its radially inner surface 18, the body 11 is also provided with a circularly symmetrical peripheral groove 19, in which an elastomer O-ring seal 20 is received.

The female element A comprises a main body 40 that can be seen more particularly in FIG. 12, and in which a first piston 50 and a second piston 52 are received, the pistons being visible in FIGS. 5, 12, and 13, and being mounted respectively in a first bore 54 and in a second bore 56 that are aligned with each other and that have a common central axis Y-Y′ that is perpendicular to the axis X-X′. The main body 40 forms a channel 42 through which pressurized fluid can flow from a chamber 44 defined between facing surfaces 502 and 522 of the pistons 50 and 52. The surfaces 502 and 522 constitute two opposite surfaces perpendicular to the axis Y-Y′ and in contact with the fluid flowing through the coupling element A when the valve 200 is open.

The main body 40 is extended by a pipe 46 that is terminated by a flange 462 to which the pipe C₁ is connected. A channel 48 connects the internal volume 460 of the pipe 46 to an annular space 542 around the piston 50.

Thus, the internal volume 460 of the pipe 46, the channel 48, the space 542, the chamber 44 and the channel 42 together define a duct 400 through which pressurized fluid can flow inside the female coupling element A from the pipe C₁. The pressurized fluid is caused to flow in the duct 400 by a valve 200 in which the pistons 50 and 52 constitute moving elements.

The channel 42 extends both inside a solid portion 40A of the main body 40 and inside an inner sleeve 60 that extends the portion 40A along X-X′ towards the front of the element A. The inner sleeve 60 is cylindrical, of circular section and hollow. The inner sleeve 60 is shown in the figures as being integral with the portion 40A of the body 40. In a variant, the inner sleeve 60 may be mounted on the body, e.g. by screw-fastening or by welding.

The fact that the inner sleeve 60 is provided in the main body 40 makes it possible to minimize the disturbance of the fluid flow and to limit the number of parts in contact with the fluid, which constitutes an advantage in particular when the fluid is hydrogen.

An auxiliary body 70 is mounted on the main body 40 with it being possible for said auxiliary body to move axially relative to the main body, parallel to the axis X-X′. The auxiliary body 70 is subjected to the action of a spring 789 that urges it back along the axis X-X′ towards the front of the female element A.

The auxiliary body 70 defines two recesses 72 and 74 in which two locking members 82 and 84 are received. These locking members are mounted to move between a first position in which they are fully engaged in the recesses 72 and 74, so that they do not project radially from the auxiliary body 70 towards the axis X-X′, and a second position in which said locking members 82 and 84 project from the recesses 72 and 74 towards the axis X-X′, to the extent that they can be partially engaged in the groove 17 in the body 11 and can thus retain the male element B in the locked position in the auxiliary body 70. The locking members 82 and 84 have opposite surfaces in the shape of segments of a sphere, and the recesses 72 and 74 are also in the shape of segments of a sphere, thereby imparting good radial compactness to the auxiliary body 70.

In variants of the invention that are not shown, the locking members may be studs disposed in recesses that are inclined relative to the axis X-X′, as described in EP-1 531 297, or balls, as described in EP-A-1 561 991. The present invention is applicable independently of the exact type of the locking members used.

A control ring 90 is slidably mounted along the axis X-X′ around the auxiliary body 70 that has a radially outer surface of circular section. The ring 90 is subjected to the action of a spring 92 that urges it back towards the solid portion 40A of the main body 40.

Mechanical link means (not shown) connect the ring 90 to the locking members 82 and 84, so that, by sliding around the auxiliary body 70, the ring 90 makes it possible to control the positions of the locking members 82 and 84 along the axis X-X′ and relative to their respective recesses 72 and 74. Thus, it is possible to lock the male element B in the female element by moving the ring 90 relative to the auxiliary body 70 towards the front of the element A, i.e. in a direction such that the locking members 82 and 84 are brought from their above-mentioned first position to their above-mentioned second position.

The auxiliary body 70 surrounds the inner sleeve 60 and defines a volume 76 for receiving the front edge 111 of the body 11 of the male element.

The auxiliary body 70 forms a cylindrical hollow outer sleeve 78 that is coaxial with the inner sleeve 60 and that extends radially between the recess 76 and the inner sleeve 60, and on which the force from the spring 789 is exerted. Reference 62 designates the end of the inner sleeve 60 that is opposite from the portion 40A of the main body 40 and that is surrounded by the outer sleeve 78 in the position shown in FIGS. 1 to 7.

The portions 60 and 78 of the element A together constitute a hollow end-piece 80 inside which a portion of the fluid flow duct 400 is defined and that can come to bear against the O-ring seal 20, as appears from the following explanations.

When the female coupling element A is in a decoupled configuration, the outer sleeve 78 surrounds the end 62 to the extent that their respective front edges are substantially aligned in a direction perpendicular to the axis X-X′.

A discharge duct 100 is provided transversely in the auxiliary body 70 and is extended to the level of the radially outer surface 64 of the inner sleeve 60.

The discharge duct 100 communicates with the fluid flow duct 400 through an annular space 300 defined between firstly the radially outer surface 64 of the inner sleeve 60 and secondly the radially inner surface 79 of the outer sleeve 78. The annular space 300 is in fluid communication with the discharge circuit 100 regardless of the relative position of the inner sleeve 60 and of the outer sleeve 78 while the coupling R is operating. In addition, the annular space 300 opens out axially and onto the fronts of the sleeves 60 and 78 in a circular volume around the axis X-X′, said volume being in communication with the channel 42 of the fluid flow duct 400. The fact that the radial thickness e₃₀₀ of the annular space 300 is very small, of the order of 0.025 millimeters (mm), combined with the fact that the inner sleeve 60 and the outer sleeve 78 are coaxial imparts good radial compactness to the female element A

A lever 120 is hinged to the cam 122 by means of a stud 124, the longitudinal axis of which is referenced A₁₂₄. In practice, two cams 122 are mounted on either side of the body 40 as can be seen in FIG. 2, and the lever 120 is hinged to these two cams, around a common axis A₁₂₄. In FIG. 3, the portion of the lever 120 that is hinged to the cam 122 is not shown, in view of the section plane. The trace of this hinge portion can be seen in chain-dotted lines in FIG. 6.

The lever 120 is provided with a first slot 126 in which a roller 130 mounted to rotate about a stud 132 is engaged. The lever 120 is also provided with a second slot 128 that is masked in FIG. 1 and in which a roller 134 mounted to pivot about a stud 136 is engaged.

The studs 132 and 136 are secured to or integral with respective ones of a first column 142 and of a second column 144 that extend between a first plate 152 and a second plate 154 on which the pistons 50 and 52 are respectively mounted. The columns 142 and 144 constitute mechanical link means between the plates 152 and 154 and they are also the means common to the pistons 50 and 52 and on which the wheels 130 and 134 act to cause the pistons 50 and 52 to move in the opening direction or the closure direction for opening or closing the valve 200. The columns 142 and 144 are slidably mounted in two bores 145 and 146 that are provided in external portions 147 and 148 of the main body 40. The bores 145 and 146 are centered on axes Y₁₄₅ and Y₁₄₆ parallel to the axis Y-Y′. The axes Y₁₄₅ and Y₁₄₆ lie on either side of the plane formed by the axes X-X′ and Y-Y′.

In FIGS. 5 and 13, the elements 132, 136, 142, 144, 152, and 154 are shown as formed integrally in one piece. In practice they may be made up of a plurality of elements assembled together by any suitable means, in particular by welding or screw-fastening.

Given the manner in which it is mounted on the main body 40, the lever 120 is suitable for pivoting sequentially about the wheels 130 and 134, and then about the axis A₁₂₄ and vice versa.

Each cam 122 bears against a roller 94 that is secured to the control ring 90 through a clevis 96.

Each cam 122 is secured via its stud 124 to a second cam 162 that is slidably mounted in a recess 73 formed in the auxiliary body 70. The direction of sliding D₁₆₂ of a cam 162 in its recess 73 is imposed by the geometrical shape of the auxiliary body 70. This direction of sliding is parallel to the axis Y-Y′. As can be seen in FIG. 8, for example, for the cam 162 shown in FIG. 1, each cam 162 is disposed between two wheels 172 and 174. Each wheel 172 is mounted to turn about a stud 43 secured to or integral with the main body 40, and each wheel 174 is mounted to turn about a stud 45 secured to or integral with the auxiliary body 70.

Operation is as follows: Starting from a configuration in which the female element A and the male element B are spaced apart, the male element B is fitted into the female element A by causing it to move in translation along the axis X-X′ in a manner such that the seal 20 comes into abutment against the front edge of the outer sleeve 78. This is the configuration shown in FIGS. 1 to 5. The contact between the hollow end-piece 80 and the male element B in this configuration offers the advantage of imparting good axial compactness to the coupling R. In this configuration, in which the female element A and the male element B are interfitted and not locked, two springs 182 and 184 disposed between the plate 154 and the main body 40 together with the pressure of the fluid in the annular space 542 exert a force on the assembly made up of the parts 50, 142, 144, 152, and 154 that presses the piston 50 against a corresponding seat 47 formed by the main body 40 and closes the valve 200.

Starting from this configuration, the operator actuates the lever 120 by exerting a force on it that urges it to pivot towards the pipe 46, as indicated by the arrow F₁. The lever 120 then pivots about the wheels 130 and 134, thereby causing the cams 122 to move in the direction indicated by the arrow F₂ in FIG. 3, the direction of this movement being imposed by the cams 162 being guided in their recesses 73. The lever 120 pivots about the wheels 130 and 134 while being guided by their outside surfaces because the forces to be overcome to move the auxiliary body 70 and the control ring 90, parallel to the axis X-X′, relative to the main body 40, are smaller than the forces to be overcome to move the wheels 130 and 134 and the pistons 50 and 52 parallel to the axis Y-Y′. In view of the fact that the resilient force exerted by the spring 92 on the control ring 90 is less than the resilient force exerted by the spring 789 on the auxiliary body 70, and because of the geometrical shape of the cams 122, the effect of these cams being moved in the direction indicated by arrow F₂ is to push the rollers 94 back towards the front of the male element A. This movement of the rollers 94 causes the control ring 90 to be moved along the axis X-X′ against the resilient force exerted by the spring 92, thereby, in view of the drive link means between the ring 90 and the locking members 82 and 84, causing the locking members 82 and 84 to come out of their respective recesses 72 and 74 to the extent that they engage in the groove 17, as shown in FIGS. 6 and 7. The locking members thus go from their first position to their second position. The body 11 of the male element B is thus locked in the auxiliary body 70 of the female element A.

During the movement of the control ring 90, the cam 162 and the auxiliary body 70 do not move along the axis X-X′ relative to the main body 40. The cam 162 co-operates with the wheel 172 at a portion 162 b of the stepped surface 162 a of the cam 162 that is perpendicular to the axis X-X′. Thus, the front ends of the inner sleeve 60 and of the outer sleeve 78 remain aligned in a direction perpendicular to the axis X-X′.

By continuing to move the lever 120 about the wheels 130 and 134, the user continues to move the cams 122 and 162 in the direction indicated by arrow F₂, thereby moving the cams 162 towards the rear of the female element A relative to the main body 40 against the spring 789. Each cam 162 bears against a wheel 172 or the like that is secured to the main body 40 through the stud 43. By moving downwards in FIG. 7, the cam 162 is pushed back towards the rear of the main body 40 because a surface of the stepped cam surface 162 a that is offset forwards along the axis X-X′ relative to the portion 162 b comes to bear against the radially outer surface of the wheel 172.

Since each cam 162 is engaged in a recess 73 in the auxiliary body 70, this rearward movement of the cam 162 along the axis X-X′, in the direction indicated by arrow F₃ in FIG. 8, generates a corresponding movement indicated by arrow F₄ for the auxiliary body 70. The effect of this movement as indicated by F₄ is to bring the body 11 as captive of the auxiliary body 70 to bear against the end of a stud 49 formed by the main body 40 and that extends parallel to the inner sleeve 60 at a distance therefrom. This movement also causes the sleeve 78 to move along the axis X-X′ relative to the inner sleeve 60 towards the rear of the female element A. The front edges of the inner sleeve 60 and of the outer sleeve 78 are therefore no longer in alignment.

While the auxiliary body 70 is moving as indicated by arrow F₄ by co-operation between the cam 162 and the wheel 172, the control ring 90 that is constrained to move with the cam 162 along the axis X-X′ undergoes the same movement as the auxiliary body 70.

Within the reference frame of the male element B that is the reference frame of the body 11 and of the seal 20, the effect of the above-mentioned movement of the auxiliary body 70 relative to the main body 40 is to cause the end 62 of the inner sleeve 60 to advance towards the seal 14 and to bring the outside surface of the inner sleeve 60 into contact with the seal 20. As appears from FIG. 9, the effect of this movement is to press the O-ring seal 20 firmly against the bottom 19 a of the groove 19.

The end 62 is beveled on the outside. It is defined by a frustoconical surface 66 converging towards the front of the female element A and of half-angle α at the vertex that has a value lying in the range 10° to 40°. Preferably, the value of the angle α is about 25°. This geometrical shape of the end 62 enables it to interact with the seal 20 without “marking” or wearing said seal excessively during successive manipulations of the coupling R.

In addition, the front end of the outer sleeve 78 is beveled on the outside and defined by a frustoconical surface 782 converging towards the front and of half-angle β at the vertex that lies in the range 60° to 80°, and that is preferably about 72°. This bevel generates a wedge effect that retains the seal 20 in the groove 19, in spite of the friction exerted by the outside surface of the inner sleeve 60 as it moves relative to the outer sleeve 78 for emptying purposes.

Starting from the configuration of FIGS. 8 and 9, when the user continues to pivot the lever 120 in the direction indicated by arrow F₁, said lever no longer pivots about the rollers 130 and 134 but rather about the axis A₁₂₄. At this stage, the body 11 that is constrained to move in translation with the auxiliary body 70 is in abutment against the stud 49 of the main body 40, thereby making it impossible for the cam 162 to move as indicated by arrow F₂ because the wheel 172 would have to co-operate with a surface of the cam 162 that is offset forwards along the axis X-X′. The drive linkage described thus makes it possible to make opening of the valve 200 dependent on the presence of a male element B locked inside the female element A. The cam 162 has then reached an end-of-stroke position in which the stud 124 is held stationary. Thus, the effect of continuing to move the lever 120 in the direction indicated by arrow F₁ is to transmit to the rollers 130 and 134 a force represented by arrows F₅ in FIGS. 10 and 13. This force moves the equipment made up of the parts 50, 52, 142, 144, 152, and 154 against the force exerted by the springs 182 and 184 and by the pressure of the fluid in the annular space 542. This equipment constitutes the moving portion of the valve 200 formed in the female element A, while the main body 40 constitutes the stationary portion of the valve 200 and carries the seat 47.

The geometrical shape of the slots 126 and 128 makes them compatible with the lever 120 pivoting about the axis A₁₂₄, while the axis A₁₃₂ remains in the same position along the axis X-X′ during the movement of the moving equipment of the valve 200.

The parts 142, 144, 152, and 154 constitute mechanical link means between the upstream piston 50 and the downstream piston 52, these link means being disposed outside the fluid flow duct 400 in the female element A. As a result, the mechanical link means are not subjected to the chemical action of the fluid flowing through the coupling R, and do not hinder flow of the fluid.

An O-ring seal 190 is mounted in the main body 40 at the seat 47 against which a surface 504 of the piston 50 can come to bear, which surface is in the shape of a segment of a sphere. The piston 50 is formed integrally in one piece and it has an intermediate portion 505 that is circularly cylindrical and that is engaged with a small amount of clearance into the bore 54 that is also circularly cylindrical. An O-ring seal 192 is disposed in a groove 194 provided in the radial surface of the bore 54 and provides sealing between the annular space 542 and the outside of the body 40. The sealing section between the piston 50 and the main body 40 at the seal 192 corresponds to a disk of diameter equal to the diameter D₅₀₅ of the portion 505.

Reference D₅₀₄ designates the diameter of the sealing section between the piston 50 and the main body 40 at the seal 190 when the valve is in the closed configuration. The diameter D₅₀₄ is greater than the diameter D₅₀₅. As a result, when the valve 200 is in the closed configuration, i.e. when the piston 50 is bearing against the seat 47, the force exerted by the fluid on the piston 50 in the closing direction for closing the valve, which force is proportional to the diameter D₅₀₄, is greater than the force from the fluid on the piston 50 in the opening direction, which force is proportional to the diameter D₅₀₅, and the resultant of the pressure forces to which the piston 50 is subjected tends to press said piston against its seat.

The springs 182 and 184 close the valve in the event of insufficient pressure upstream from the seat 47. The difference between the diameters D₅₀₅ and D₅₀₄, which difference is about 10%, remains small, thereby resulting in a small valve opening force in spite of the high pressure.

In the example shown in the figures, the piston 50 is circularly symmetrical. However, it may have some other geometrical shape, and the default force for pressing the piston 50 against its seat 47 is obtained so long as the area of the cross-section of the piston 50, measured where it is in leaktight contact with the bore 54 perpendicularly to the axis Y-Y′, is less than the area of the cross-section of the piston 50 where it bears against the seat 47 when the valve 200 is in the closed position.

In the direction Y-Y′, the piston 50 has a head 506 connected to the portion 505 via a rod 507 of small diameter. The piston 50 is mounted on the plate 152 by inserting the head 506 into a recess 156 formed in the side of the plate 152 that is opposite from the main body 40. Radial clearance J₁ is provided between the rod 507 and the edge of an orifice 157 through which the rod passes, at the bottom of the recess 156. This radial clearance J₁ makes it possible to adjust the position of the piston 50 relative to the plate 152, in a direction perpendicular to the axis Y-Y′.

In addition, the head 506 is mounted in the recess 156 with axial clearance J₂, parallel to the axis Y-Y′. This makes it possible to adjust the axial position, along the axis Y-Y′, of the piston 50 relative to the plate 152, in particular when the piston comes to bear against its seat 47.

The piston 52 is circularly cylindrical and the bore 56 has a corresponding circular section. An O-ring seal 196 is installed in a groove 198 provided in the radial surface of the bore 56. The sealing section for sealing between the piston 52 and the bore 56 at the seal 196 is provided on a disk of diameter equal to the diameter D₅₂₀ of the piston 52. The diameter D₅₂₀ is greater than the diameter D₅₀₅ so that, when the valve is in the open configuration shown in FIG. 13, the force exerted by the fluid on the piston 52, in particular at its surface 522, directed in the closing direction for closing the valve, and proportional to the diameter D₅₂₀, is greater than the force from the fluid on the piston 50, in particular at its surface 502, directed in the opening direction and proportional to the diameter D₅₀₅, and the resultant of the pressure forces due to the presence of the fluid in the space 542 and in the chamber 44 and that are applied to the moving equipment tends to re-close the valve.

This operation can be obtained so long as the area of the cross-section of the piston 52 where it is in leaktight contact with the bore 56 is greater than the area of the cross-section of the piston 50 where it is in leaktight contact with the bore 54.

The difference between the diameters D₅₀₅ and D₅₂₀ is about 4% and is therefore not visible on the drawings.

When the valve is open, and due to the forces exerted by the pressure from the fluid on the pistons 50 and 52, the columns 142 and 144 are subjected to non-harmful traction stresses because the columns 142 and 144 are disposed outside the flow duct 400 and are thus dimensionable without disturbing passing of the fluid.

The piston 52 has a head 526 and a rod 527 of geometrical shapes similar to those of the elements 506 and 507. A recess 158 and an orifice 159 comparable to the recess 156 and to the orifice 157 are provided in the plate 154 and they make it possible to receive, respectively, the head 526 and the rod 527 with radial clearance J₃, thereby making it possible to adjust the position of the piston 52 relative to the plate 154 perpendicularly to the axis Y-Y′. The recesses 156 and 158 receive the head 506 and 526 with radial clearances respectively at least equal to or indeed greater than the clearances J₁ and J₃. In a variant, the clearances J₁ and J₃ to be taken into consideration are defined at the heads 506 and 526, the orifices 157 and 159 receiving the rods 507 and 527 with at least equal or indeed greater radial clearance.

Due to the valve 200 being opened, the pressurized fluid coming from the pipe 46 flows into the channel 42 after having passed through the portions 48, 542, and 44 of the flow duct 400, at pressure sufficient to push the non-return valve member 13 back into the body 11 of the male element, so that said male element moves away from the seal 14 and allows the fluid to pass into the channel 12. When the male and female elements are in the locked configuration, with the valve 200 open, allowing the fluid to flow, said pressure is also exerted on the seal 20 which is thus pressed against the bottom 19 a of the groove 19, against the outside surface of the sleeve 60, and against the front end of the outer sleeve 78. In this position shown in FIG. 11, the seal 20 prevents the fluid from passing both through the interface zone between the body 11 and the outer sleeve 78, i.e. through the annular space 350 defined between the body 11 of the male element B and a portion of the auxiliary body 70 of the female element A, and also through the interface zone between the inner sleeve 60 and the outer sleeve 78, i.e. the annular space 300. In this way, the seal 20 prevents pressurized fluid from flowing both towards the outside of the bodies 11 and 70 and also towards the discharge duct 100. This double-sealing function of the seal 20 makes it possible to simplify construction and to save money.

When the valve is to be re-closed before decoupling the male and female elements B and A, the operator pivots the lever 120 in the direction indicated by arrow F₆ in FIG. 14, i.e. in the direction opposite to the direction indicated by arrow F₁. By a movement that is the reverse of the movement explained above with reference to the lever 120, the effect of the operator pivoting the lever in this direction is to bring the piston 50 to bear against its seat 47. The valve is thus closed, interrupting the flow of fluid. Since the valve member 13 is no longer pushed back into the channel 12 by the pressure of the fluid flowing in the male element B, it is brought back against its seat by a spring (not shown). The effect of continuing to move the lever 120 in the direction indicated by arrow F₆ is to move the cams 162 and 122 in the direction indicated by arrow F₇ in FIG. 14. This movement of the cams 162 that are still engaged between the wheels 172 and 174 allows the auxiliary body 70 to move relative to the main body 40 towards the front of the female element A, i.e. leftwards in FIG. 14, as indicated by arrow F₈ in FIG. 14. The forward movement of the auxiliary body 70 takes place by means of the action of the spring 789 that is exerted on the outer sleeve 78 and by means of the pressure of the captive fluid that is exerted on the body 11 of the male element B, urging it to move back out of the female element A and holding the locking members 82 and 84 in the groove 17.

As appears from FIG. 15, the effect of this movement is to bring the outer sleeve 78 into a configuration in which its front edge is substantially aligned, in a direction perpendicular to the axis X-X′, with the front edge of the end 62. In this configuration in which the pressurized fluid that is captive between the piston 50 and the valve member 13 needs to be emptied, the O-ring seal 20 is pressed against the bottom 19 a of the groove 19 and against the front end of the sleeve 78, but is no longer in contact with the sleeve 60. The shape of the outer sleeve 78, and in particular the value of the angle β, is chosen so as not to mark the seal 20 in this position.

The annular space 300 opens out directly into the groove 19 that communicates with a volume formed by the interconnection of the fluid flow duct 400 and of the flow channel 12 upstream from the valve member 13. The space 300 opens out into the groove 19 in axial manner and at the front edges of the inner sleeve 60 and/or of the outer sleeve 78.

In this configuration in which the male element B is locked in the female element A, with the valve 200 closed, and the female element emptied, the O-ring seal 20 prevents fluid from flowing into the interface zone between the outer sleeve 78 and the body 11 of the male element B, i.e. into the annular space 350, so that the male element B and the female element A remain in leaktight contact and so that the fluid is not discharged towards the outside of the assembly formed by the bodies 11 and 70. Conversely, the O-ring seal 20 no longer prevents fluid from flowing into the interface zone 300 between the sleeves 60 and 78, so that the pressurized fluid can flow through the annular space 300 and into the discharge duct 100, as indicted by the flow arrows E in FIG. 15.

Thus, the residual pressurized fluid that is held captive downstream from the seat 47 in the chamber 44 and in the channel 42 after closure of the valve 200 and of the valve member 13 can be removed via the discharge duct 100. When the value of the pressure downstream from the seat 47 becomes less than a certain value, determined for the safety of the user, the spring 92 manages to push back the control ring 90, the locking members 82 and 84 disengage from the groove 17, and the male element B can be disengaged from the female element A.

By means of the positioning of the sleeves 60 and 78 and of the O-ring seal 20, an automatic flow control function is obtained for controlling the flow of the pressurized fluid towards the discharge duct 100, this automatic function not requiring any particular manipulation by a user because it can result, automatically, from the movements of the component parts of the coupling during the successive steps of coupling, of opening the valve 200, of closing the valve 200, and of de-coupling.

In the second embodiment of the invention shown in FIGS. 16 and 17, elements analogous to the elements of the first embodiment bear like references.

In this embodiment, an O-ring seal 22 is interposed between the end face 784 of the sleeve 78 and the front edge 111 of the body 11. This O-ring seal 22 provides sealing at the interface 350 between the bodies 11 and 70. The inner sleeve 60 bears against the O-ring seal 20 while pressurized fluid is flowing through the coupling, as shown in FIG. 16. It then presses the seal 20 against the bottom 19 a of the groove 19.

As shown in FIG. 17, after the valve of the coupling has been closed, and on decoupling the male and female elements of the coupling, the sleeve 78 is pushed back in the direction indicated by arrow F₈. The effect of this is to push the body 11 back in the same way so that the end 62 of the inner sleeve 60 is spaced apart from the O-ring seal 20, thereby leaving a passageway available for the flow E of residual pressurized fluid towards the discharge duct 100, through the annular space 300 defined between the outside surface of the end 62 of the inner sleeve 60 and the outside surface of the outer sleeve 78.

In the third embodiment of the invention, shown in FIG. 18, elements analogous to the elements of the first embodiment bear like references. The valve 200 of this embodiment has a first piston 50 and a second piston 52 between which a ball 58 is disposed along the axis Y-Y′, which ball is suitable for coming to bear against a seat 47 formed by the main body 40 of the female element of the coupling and that is equipped with an O-ring seal 190. The pistons 50 and 52 co-operate with the ball 58 at their respective end surfaces 502 and 522. These contacts may be simultaneous or non-simultaneous. An annular space 542 is defined around the piston 50, and around the ball 58, upstream from the seal 47, while a flow chamber 44 is defined downstream from said seat. The chamber 44 is a portion of a flow duct 400 for enabling pressurized fluid to flow in the main body 40 of the female element of the coupling A. When the valve is in the closed configuration, the piston 50 comes to bear indirectly against the seat 47 via the ball 58 that the piston 50 pushes against said seat, by means of its end surface 502.

In order to open the valve, the piston 52, via its end surface 522, pushes the ball 58 so as to lift it off the seat 47.

In an optional aspect of the invention that is not shown, a resilient device may be interposed between the surface 502 of the piston 50 and the ball 58 so as to maintain contact between the piston 50 and the ball 58 despite the axial clearance between the piston 50 and the plate 152. As in the first embodiment, the pistons 50 and 52 are implemented by mechanical link means made up of two columns 142 and 144, and of two plates 152 and 154 that are disposed outside the flow duct 400 through which the pressurized fluid can flow.

In a closed configuration shown in FIG. 18, the ball 58 rests on the seat 47. The fluid present in the annular space 542 subjects the piston 50 and the ball 58 to compression stress only.

Two springs 182 and 184 exert a force on the equipment formed by the parts 50, 52, 142, 144, 152, and 154, which force urges the valve to re-close by default.

When the valve 200 is to be opened, action is taken on the columns 142 and 144 so as to exert thereon a force F₉ that is parallel to the axis Y-Y′ along which the pistons move, in a direction in which the piston 50 is moved away from the seat 47. This force may be exerted by wheels such as the wheels 130 and 134 mentioned for the first embodiment, or by any other appropriate means (not shown).

In this embodiment, the sealing sections may also be slightly different, as mentioned for the first embodiment, so as to make closure secure and so as to facilitate opening. The diameter D₅₈ where the ball 58 is in contact with the seat 47, corresponding to the sealing section between the ball 58 and the seat 47 at the seal 190, is slightly greater than the diameter D₅₀₅ so as to limit the opening force exerted by the piston 52 on the ball 58.

The technical characteristics of the above-described embodiments may be combined within the ambit of the present invention. 

The invention claimed is:
 1. A female quick-connect coupling element for releasably joining together pipes for pressurized fluid comprising, a body having a fluid flow duct and a valve for controlling flow of fluid through the duct, the valve having a first piston and a second piston that are mounted to move in translation in opposing relationship and along a common axis relative to the body, the first piston being cooperatively engageable with a valve seat provided within the body of the female element so as to close the valve, the first and second pistons are interconnected by a mechanical link assembly, each of the first and second pistons defines one of two opposite and facing surfaces in contact with the fluid when the valve is open, and, due to forces exerted by the fluid on the first piston and the second piston, the mechanical link assembly is subjected to traction stresses when the valve is open, and the mechanical link assembly between the first and second pistons being disposed outside the fluid flow duct.
 2. The female quick-connect coupling element according to claim 1, wherein the mechanical link assembly between the first piston and the second piston includes a first plate drivingly linked to the first piston, a second plate drivingly linked to the second piston, and at least one link member interconnecting the first and second plates, wherein the first and second plates are disposed on either side of a portion of the flow duct that is defined between opposite surfaces of the first and second pistons, and wherein the at least one link member is mounted to move relative to the body of the female element, along an axis parallel to the axis along which the first and second pistons move relative to the body.
 3. The female quick-connect coupling according to claim 2, including two link members between the first plate and the second plate, which link members are mounted to slide along the common axis along which the first and second pistons move in two recesses provided in the body of the female element.
 4. The female quick-connect coupling element according to claim 2, wherein at least one of the first and second pistons is partially inserted into a corresponding recess in a plate to which the at least one of the first and second pistons is drivingly linked, and wherein radial clearance is provided between the at least one of the first and second pistons and the corresponding recess.
 5. The female quick-connect coupling element according to a claim 2, wherein the first piston is partially inserted into a corresponding recess in the first plate, and wherein radial clearance is provided between the first piston and the corresponding recess.
 6. The female quick-connect coupling element according to claim 2, wherein the mechanical link assembly is integrally formed.
 7. The female quick-connect coupling element according to claim 1, wherein the first piston is mounted to slide in leaktight manner in a first bore in the body, and wherein the second piston is mounted to slide in leaktight manner in a second bore in the body, and wherein the first bore and the second bore are aligned with each other along the common axis.
 8. The female quick-connect coupling element according to claim 7, wherein an area of a cross-section of the second piston where the second piston is in leaktight contact with the second bore is greater than an area of a cross-section of the first piston where the first piston is in leaktight contact with the first bore.
 9. The female quick-connect coupling element according to claim 1, wherein the first piston is mounted to slide in leaktight manner in a bore in the body, and wherein a cross-section of the first piston where the first piston engages the valve seat has an area greater than an area of a cross-section of the first piston where the first piston is in leaktight contact with the bore.
 10. The female quick-connect coupling element according to claim 1, including at least one lever that is hinged relative to the body about an axis perpendicular to the common axis along which the first and second pistons move, the lever is drivingly linked to the mechanical link assembly, wherein a first movement in rotation of the lever about the axis causes the mechanical link assembly and the first and second pistons to move in translation in a first direction along the common axis, and wherein a second movement in rotation of the lever about the axis, opposite to the first movement in rotation, causes the mechanical link assembly and the first and second pistons to move in translation in a second direction opposite to the first direction along the common axis.
 11. The female quick-connect coupling element according to claim 1, wherein an end of the first piston has a surface that is partially spherical and that is configured to bear against the valve seat when the valve is in a closed configuration.
 12. The female quick-connect coupling element according to claim 1, wherein the first piston co-operates with the valve seat via a ball engageable against the valve seat, and wherein the first piston and the second piston contact the ball at their two opposite and facing surfaces.
 13. A quick-connect coupling for releasably joining together pipes for pressurized fluid, the coupling comprising a male element and a female element, which elements fit one into the other, the female element including a body having a fluid flow duct and a valve for controlling flow of fluid through the duct, the valve having a first piston and a second piston that are mounted to move in translation in opposing relationship and along a common axis relative to the body, the first piston being cooperatively engageable with a valve seat provided within the body of the female element so as to close the valve, the first and second pistons are interconnected by a mechanical link assembly, each of the first and second pistons defines one of two opposite and facing surfaces in contact with the fluid when the valve is open, and, due to forces exerted by the fluid on the first piston and the second piston, the mechanical link assembly is subjected to traction stresses when the valve is open, and the mechanical link assembly between the first and second pistons being disposed outside the fluid flow duct.
 14. The quick-connect coupling for releasably joining together pipes for pressurized fluid according to claim 13, wherein the mechanical link assembly between the first piston and the second piston includes a first plate drivingly linked to the first piston, a second plate drivingly linked to the second piston, and at least one link member interconnecting the first and second plates, wherein the first and second plates are disposed on either side of a portion of the flow duct that is defined between opposite surfaces of the first and second pistons, and wherein the at least one link member is mounted to move relative to the body of the female element, along an axis parallel to the axis along which the first and second pistons move relative to the body.
 15. The quick-connect coupling for releasably joining together pipes for pressurized fluid according to claim 14, wherein the mechanical link assembly is integrally formed. 